This invention relates to driven clutch disk assemblies adapted for use in dry friction clutches. More particularly, the invention relates to the use of cushioned friction systems within such disk assemblies for the purpose of reducing friction forces during initial clutch engagement.
The conventional clutch disk assembly for automotive and other vehicular use includes a hub having a flanged portion secured to an integral flat disk. The disk typically has a plurality of friction pads riveted or bonded to its sides. The disk is positioned, by means of the hub on a transmission input shaft, between a flywheel and a reciprocal pressure plate driven by an internal combustion engine or electric motor. Upon depression of a clutch pedal, the pressure plate is axially moved away from the flywheel to disengage the clutch, and, upon release of the pedal, the pressure plate moves the disk toward the flywheel to engage the disk between the pressure plate and flywheel.
In clutches without cushioned friction systems, the entire friction contact area of the clutch disk becomes substantially engaged between the flywheel and pressure plate simultaneously, wherein the clutch may chatter due to the typically aggressive, grabby nature of the friction material; particularly, where such friction material is metallic. Such chatter is generally evidenced as noise and vibration, and occurs whenever the operator first engages the clutch. Upon initial clutch engagement in such prior art systems, torque demand tends to exceed clutch capacity, wherein the friction pads of the disk alternately grab and break loose, resulting in jerky starting movement of the vehicle.